U.S. patent application number 14/612099 was filed with the patent office on 2015-07-23 for wireless cardioresonance stimulation.
The applicant listed for this patent is Cardiola Ltd. Invention is credited to Armin Eggli, Larry Lapanashvili, Jean-Felix Perotto, Christian Piguet, Christian Stuerzinger, Thomas Zimmermann.
Application Number | 20150202435 14/612099 |
Document ID | / |
Family ID | 53543889 |
Filed Date | 2015-07-23 |
United States Patent
Application |
20150202435 |
Kind Code |
A1 |
Stuerzinger; Christian ; et
al. |
July 23, 2015 |
WIRELESS CARDIORESONANCE STIMULATION
Abstract
An apparatus for the cardio-synchronised stimulation of skeletal
or smooth muscle, but excluding the heart muscles, in a
counterpulsation mode of a patient. The apparatus comprises an
active and a passive electrode for attachment to said patient, a
signal processor having a configuration input for varying a time
delay associated with counterpulsation mode stimulation, and a
sensing system for sensing information relating to the performance
of the patient's heart and for transmission of information signals
to said signal processor, said signal processor producing control
signal information relating to stimulation signals to be applied to
said active electrode in a counterpulsation mode, a stimulation
signal generator associated with said active electrode for
generating stimulation signals, wireless transmission means for
transmitting said control signal information from said signal
processor to said stimulation signal generator whereby said
stimulation signal generator applies stimulation signals to said
active electrode in accordance with said signal information.
Inventors: |
Stuerzinger; Christian;
(Winterthur, CH) ; Lapanashvili; Larry;
(Winterthur, CH) ; Zimmermann; Thomas;
(Schaffhausen, CH) ; Eggli; Armin; (Uhwiesen,
CH) ; Piguet; Christian; (Neuchatel, CH) ;
Perotto; Jean-Felix; (Neuchatel, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cardiola Ltd |
Winterthur |
|
CH |
|
|
Family ID: |
53543889 |
Appl. No.: |
14/612099 |
Filed: |
February 2, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14331127 |
Jul 14, 2014 |
8954154 |
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14612099 |
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14032168 |
Sep 19, 2013 |
8812118 |
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14331127 |
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11667622 |
Dec 14, 2007 |
8577471 |
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PCT/EP2005/009384 |
Aug 31, 2005 |
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14032168 |
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Current U.S.
Class: |
607/48 |
Current CPC
Class: |
A61N 1/36034 20170801;
A61B 5/0456 20130101; A61B 5/4836 20130101; A61B 5/0245 20130101;
G16H 20/30 20180101; A61N 1/36031 20170801; A61B 5/7232 20130101;
A61B 5/0006 20130101; G16H 40/67 20180101; A61N 1/36003 20130101;
A61B 5/6898 20130101 |
International
Class: |
A61N 1/36 20060101
A61N001/36 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 16, 2004 |
EP |
04027227.0 |
Claims
1. An apparatus for cardio-synchronised stimulation of skeletal or
smooth muscle, but excluding heart muscles, in a counterpulsation
mode of a patient having a cardiovascular system and a heart having
a heart rate, the apparatus comprising: at least one active
electrode and at least one passive electrode configured for
attachment to said patient at positions at which the electrodes are
in communication with said skeletal or smooth muscle when said
skeletal or smooth muscle is in its original, natural position
within the patient; a signal processor having a configuration input
and configured to produce control signal information relating to
stimulation signals to be applied to said at least one active
electrode in the counterpulsation mode; a sensing system configured
to sense information relating to performance of the patient's
heart, the information comprising at least the heart rate, and to
transmit information signals relating to the information to said
signal processor; a medical evaluation unit configured to transmit
signal configuration information to the configuration input and
said signal processor being adapted to take account of said signal
configuration information when generating said control signal
information, wherein the connection between the configuration input
and the signal processor, and/or the connection between the
configuration input and the medical evaluation unit can be realized
by any device with wireless transmitter and/or receiver
capabilities.
2. The apparatus in accordance with claim 1, wherein the device is
selected from the group of devices comprising a mobile phone, a
personal digital assistant with phone function, and any standard
piece of equipment having a transceiver, a microprocessor, a memory
for storing software and data, a battery, or other source of power
and a clock; and wherein software relevant to the operation of the
signal processor and data relating to the patient's heart rhythm
and the performance of the heart and data relating to the
stimulation applied or to be applied is stored in the device.
3. The apparatus in accordance with claim 1, wherein said
information relating to the performance of the heart is selected
from the group consisting of heart rate information,
electrocardiogram (ECG) information, ECG derived information, ECG
information and information resulting from electrical stimulation,
ECG derived trigger signals, R-R information, end of T-wave
information, blood pressure information, and blood pressure derived
information.
4. The apparatus in accordance with claim 1, wherein said sensing
system comprises at least one of an invasive sensor, an intercavity
sensor, a non-invasive sensor, a body surface sensor, and a remote
sensing system detached from the patient's body.
5. The apparatus in accordance with claim 3, further comprising a
remote sensing system, wherein said signal processor is integrated
into said remote sensing system.
6. The apparatus in accordance with claim 1, said signal processor
being adapted to transmit said information to the medical
evaluation unit by one of wireless transmission and a wired
connection.
7. The apparatus in accordance with claim 1, said medical
evaluation unit being adapted to transmit signal configuration
information to said signal processor by one of wireless
transmission and a wired connection and said signal processor being
adapted to take account of said signal configuration information
when generating said control signal information.
8. The apparatus in accordance with claim 1, wherein the at least
one of active electrode comprises a plurality of active electrodes
and said at least one stimulation signal generator comprises a
respective stimulation signal generator for each active electrode,
said signal processor being configured to transmit a respective
control signal uniquely associated with a respective one of said
active electrodes to each said stimulation signal generator.
9. The apparatus in accordance with claim 1, wherein said signal
processor is configured to transmit control signal information for
a train of stimulation signals applied to one of the active
electrodes, said control signal information being selected from the
group consisting of: amplitude of the stimulation signals,
frequency of the stimulation signals, duration of the train of the
stimulation signals, width of the individual stimulation signals of
the train delay of the train of the stimulation signals relative to
a reference selected for counterpulsation stimulation, and a
recognition code by which said stimulation signal generator
recognizes that said control signal information is intended for
it.
10. The apparatus in accordance with claim 9, further comprising a
means provided at said signal processor for receiving and storing
at least one of a program for processing said control signal
information, any subsequent changes to said program, and a new
program for processing said control signal information.
11. The apparatus in accordance with claim 1, wherein the or each
said stimulation signal generator includes at least some of the
following items: its own controller, its own clock, its own
receiver antenna (RX), a power circuit, a battery, a transmitter
(RX), means for data storage, means for program storage and a
signal generator trigger.
12. The apparatus in accordance with claim 1, wherein a display is
provided at at least one of said signal processor, said
configuration input associated with the signal processor, said
stimulation signal generator and a medical evaluation unit
associated with said apparatus, said display being for the display
of at least said control signal information.
13. The apparatus in accordance with claim 12, wherein said display
is adapted to display data representing an image of the electrical
stimulation applied to said patient.
14. The apparatus in accordance with claim 13, wherein said display
is adapted to display one of an actual ECG-trace and a
representation of an ECG-trace with said image superimposed
thereon.
15. The apparatus in accordance with claim 1, wherein said medical
evaluation unit has an associated printer for printing said
data.
16. The apparatus in accordance with claim 1, wherein a code is
uniquely associated with said sensing system, said signal
processor, and said electrical stimulation signal generator.
17. The apparatus in accordance with claim 1, wherein said
stimulation signal generator comprises a member of the group
consisting of a mobile phone, a personal digital assistant with
phone function, and any dedicated or standard piece of equipment
comprising a transceiver, a microprocessor, a memory for storing
software and data, a battery or other source of power, a clock, and
necessary interface(s) for connection to the active and passive
electrodes.
18. The apparatus in accordance with claim 1, wherein said signal
processor comprises a member of the group consisting of a mobile
phone, a personal digital assistant with phone function, and any
dedicated or standard piece of equipment comprising a transceiver,
a microprocessor, a memory for storing software and data, a battery
or other source of power, and a clock.
19. The apparatus in accordance with claim 5, wherein said medical
evaluation unit comprises a member of the group consisting of is
one of a personal computer, a mainframe computer, a series of
interlinked computers, any of the foregoing with an inbuilt
transceiver, a personal digital assistant with phone function, and
any dedicated or standard piece of equipment comprising a
transceiver, a microprocessor, a memory for storing software and
data, a battery or other source of power, and a clock.
20. An apparatus for cardio-synchronised stimulation of skeletal or
smooth muscle, but excluding heart muscles, in a counterpulsation
mode of a patient having a cardiovascular system and a heart having
a heart rate, the apparatus comprising: at least one active
electrode and at least one passive electrode configured for
attachment to said patient at positions at which the electrodes are
in communication with said skeletal or smooth muscle when said
skeletal or smooth muscle is in its original, natural position
within the patient; a sensing system configured to sense sensing
information relating to performance of the patient's heart, the
sensing information comprising at least the heart rate, and to
transmit information signals comprising the sensing information to
a signal processor; the signal processor having a configuration
input and configured to produce control signal information relating
to stimulation signals to be applied to said at least one active
electrode in the counterpulsation mode; wherein the signal
processor is configured as a device with wireless transmitter and
receiver capabilities to wirelessly transmit at least one of the
control signal information and the sensing information and/or to
wirelessly receive the sensing information.
Description
CROSS-REFERENCES TO RELATED APPLICATION
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 14/331,127, filed Jul. 14, 2014, which is a
continuation of U.S. patent application Ser. No. 14/032,168, filed
Sep. 19, 2013, now U.S. Pat. No. 8,812,118, which is a divisional
of U.S. patent application Ser. No. 11/667,622, filed Dec. 14,
2007, now U.S. Pat. No. 8,577,471, which is a U.S. National Phase
of International Patent Application PCT/EP2005/009384, filed Aug.
31, 2005, which claims the benefit of European Patent Application
04027227.0, filed Nov. 16, 2004, the disclosures of which are
hereby incorporated in their entirety by reference for all
purposes.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to an apparatus for the
cardio-synchronized stimulation of skeletal or smooth muscle, but
excluding the heart muscles, in a counterpulsation mode of a
patient having a heart and a cardiovascular system. The patient can
be a human being or another mammal such as a race horse, or could
also be another animal having a heart and a cardiovascular system
such as a kangaroo (kangaroo hearts in good condition can be used
for valve replacement in humans).
[0003] References in the following to a patient will cover all the
foregoing and does not imply the patient is suffering from ill
health, since treatments using the present invention can be applied
to persons or animals which are not ill but for which a desire
exists for improvement in some aspect of their physical or mental
condition.
[0004] Apparatus and methods of this kind are, for example,
described in the International patent application with the
publication number WO 01/013990.
[0005] The applicants have established that the apparatus and
methods described in the above mentioned document WO 01/013990 can
be used to advantage for a large number of different applications.
A prime application of the apparatus and methods described is
improving the condition of the heart of a patient, for example to
reduce the likelihood of a heart attack, or to improve the
condition of the heart following a heart attack, or to assist the
patient in recovering following bypass surgery, or to treat
patients with chronic diseases, in particular chronic heart failure
and patients suffering from demetabolic syndrome. In addition it
has been found that the treatment can be used with minor
modifications in order to improve blood flow to various parts of
the body and to improve lymph drainage from various parts of the
body. Moreover, it has been shown that the treatment can be used to
improve the general condition of a wide variety of patients, such
as those who are ill or recovering from illness. A wide range of
other applications are also known and described in WO
01/013990.
BRIEF SUMMARY OF THE INVENTION
[0006] The object of the present invention is to improve the
apparatus and methods described in the document WO 01/013990, and
in particular to provide a very flexible system which enables a
patient to be treated as an outpatient, and indeed also over a long
period of time while the patient goes about his normal daily life.
It is a further object of the present invention to provide
apparatuses and methods which enable the treatment to which any
particular patient is subjected to be varied flexibly and for this
treatment to take account of developments in this type of treatment
which occur during the course of time and which are expected as
practical experience in the use of the apparatus and methods grows
and the database of successful treatments becomes larger.
[0007] A yet further object of the present invention is to minimize
the physical size of the apparatus which is associated with the
patient, so that it is of light weight, is compact, is easily
carried, is reliable and does not hinder the patient in any
significant way and so that, for example, the batteries involved
have a long working life.
[0008] A yet further object of the present invention is to provide
an apparatus and methods which enable the patient's reaction to the
treatment he is receiving to be monitored remotely and preferably
for the treatment to be modified or interrupted if monitoring shows
that the treatment is not ideally suited to the particular
patient's needs.
[0009] In order to satisfy the above object there is provided, in
accordance with the present invention, an apparatus of the
initially named kind comprising: [0010] at least one active
electrode and at least one passive electrode adapted for attachment
to said patient, [0011] a signal processor preferably having an
associated configuration input for varying at least a time delay
associated with counterpulsation mode stimulation [0012] a sensing
system for sensing information relating to the performance of the
patient's heart and for transmission of information signals to said
signal processor, [0013] said signal processor being adapted to
produce control signal information relating to stimulation signals
to be applied to said at least one active electrode in a
counterpulsation mode, [0014] a stimulation signal generator
associated with said active electrode for generating stimulation
signals [0015] wireless transmission means for transmitting said
control signal information from said signal processor to said
stimulation signal generator whereby said stimulation signal
generator applies stimulation signals to said active electrode in a
counterpulsation mode in accordance with said signal
information.
[0016] The information relating to the performance of the heart is
typically selected from the group comprising: heart rate
information, ECG information, ECG derived information, ECG
information and information resulting from electrical stimulation,
ECG derived trigger signals, R-R information, end of T-wave
information, blood pressure information and blood pressure derived
information.
[0017] The sensing system can include at least one of an invasive
sensor, an intercavity sensor, a non-invasive sensor, a body
surface sensor and a remote sensing system detached from the
patient's body.
[0018] If a remote sensing system is provided, the signal processor
can be integrated into said remote sensing system. The sensing
system is however preferably adapted for wireless transmission of
said heart information to said signal processor.
[0019] Alternatively, the sensing system can be adapted to transmit
said heart information to a medical evaluation unit associated with
the signal processor and the medical evaluation unit is then
preferably adapted to transmit signal configuration information to
the signal processor so that said signal processor takes account of
said configuration information when generating said control signal
information.
[0020] Apparatus of the above kind has the advantage that wireless
transmission from the signal processor to the stimulation signal
generator enables the signal processor to be located remote from
the patient and for the stimulation signal generator to be made
compact and small because the processing capacity necessary to
generate the trigger signals for the stimulation signal generator
is located in the separate signal processor and does not have to be
carried by the patient. In addition, the batteries associated with
the stimulation signal generator carried by the patient do not have
to provide the power for the operation of the signal processor and
can therefore be made smaller and lighter.
[0021] It is particularly beneficial if the sensing system for
sensing information relating to the performance of a patient's
heart and for transmission of information signals is adapted for
wireless transmission of said information signals, either to the
signal processor directly or possibly via the medical evaluation
unit. If such wireless transmission is used from the sensing system
then the patient is completely free of cables connecting him (or
her) to the associated apparatus, such as the medical evaluation
unit and the signal processor.
[0022] For the purpose of the present invention it is sufficient if
the sensing system for providing information relating to the
performance of the heart simply detects the R-peaks of the
patient's heart rhythm and establishes the time at which these
peaks occur in order to predict from them the end of the T-wave of
the heart rhythm for each successive heartbeat, so that stimulation
can be carried out at or close to the predicted end of the T-wave,
i.e. in the counterpulsation mode. Such information can be
delivered by an electrocardiograph or electrocardioscope but is
basically also available from a simple set of ECG electrodes which
can be combined with a simple light-weight monitor. Equally,
devices are known, such as the "Polar".TM. belt or wrist-mounted
blood pressure detectors which also reliably provide signal traces
related to the patient's heart rhythm and from which information on
the R-R peaks and/or the end of the T-wave can be derived. There
are also certain remote sensing systems which can deliver
corresponding information.
[0023] If electrical detection is used, for example using ECG
electrodes, then this has the benefit that the electrical
stimulation applied to the patient can also be picked up by the ECG
electrodes and can be displayed superimposed on the trace of the
patient's heart rhythm. In this way the synchronization of the
electrical stimulation with the patient's heart rhythm and its
effect on the patient's heart rhythm can be better assessed.
[0024] It is possible for the sensing system to have its own
transmitter for transmitting information relating to the
performance of the patient's heart to the signal processor, or to a
medical evaluation unit associated with the signal processor, and
for the stimulation signal generator to have an antenna for
receiving trigger signals and optionally other information from the
signal processor.
[0025] It is also possible for the transmitter of the sensing
system and the receiver of the stimulation signal generator to be
combined into a transceiver which is carried by the patient and
which is, for example, connected by wires to the sensing system and
to the stimulation signal generator. Such transceivers are readily
available, for example in the form of a mobile phone. Mobile phones
also have the advantage that they have significant signal
processing power, so that relevant software can be stored in them
as can data relating to the patient's heart rhythm and the
performance of the heart and data relating to the stimulation
applied or to be applied. Automatic programs can then allow the
transmission of such information to a medical evaluation unit at
intervals for assessment by a medical practitioner monitoring a
number of different patients at the medical evaluation unit.
Moreover, it is not essential for a skilled medical practitioner to
carry out all evaluations. It is also conceivable for programs to
be drawn up which enable at least routine checking to be carried
out with a medical practitioner only being alerted if something
appears to be amiss.
[0026] The signal processor can itself also be realized as a mobile
phone or as a dedicated unit similar thereto. This facilitates
communication from, for example, a mobile phone associated with the
signal sensing system and/or the stimulation signal generator since
these two systems, i.e. a mobile phone associated with the sensing
system and/or the stimulation signal generator and a mobile phone
associated with a signal processor, are inherently compatible.
Again, the processing power available in any modern mobile phone
system is sufficient for storage of the software programs needed by
the signal processor in order to analyze the information coming
from the sensing system, to predict the times at which the ends of
the T-waves occur and to generate the requisite trigger signals for
onward transmission to the stimulation signal generator. If the
signal processor is realized as a mobile phone it can be carried by
the patient--without the patient being wired to the phone--and the
mobile phone forming the signal processor can receive via its
inbuilt antenna signals transmitted from an antenna of the sensing
system (or from the stimulation signal generator) and can transmit
control signals to the stimulation signal generator.
[0027] A further advantage of using a mobile phone or a mobile
phone-like system is that communication with any other mobile phone
or mobile-phone-like system involves a telephone number which can
be used to uniquely identify the party with which communication is
to be established and the party from whom a communication is
received. Thus, one signal processor can communicate with a
plurality of different stimulation signal generators, and indeed
with a large number of them, and can provide different trigger
information and other information to each of them based on the
particular needs of the user or on the particular needs of the
associated stimulation signal generator.
[0028] It is not necessary for this communication to take place
simultaneously with a plurality of users but instead the relevant
information can be sent batch-wise at discrete times to the
individual users. For example, once a timing scheme of trigger
signals has been established it can be retained for a period of
time so long as the patient's heart rhythm remains substantially
constant. Thus, trigger timing information sent by the signal
processor to the stimulation signal generator can be stored in a
memory of the stimulation signal generator and used cyclically to
trigger the electrical stimulation. Since the stimulation signal
generator can readily communicate with the sensing system it is
also possible for the timing established by the signal processor to
be retained and repeatedly used by the stimulation signal generator
to apply stimulation to the patient until the sensing system
providing heart information shows that something has changed and
needs to be reflected by a change in the timing of the trigger
signals. Once this happens, the signal processor can be
automatically called up to provide changed timing.
[0029] It is particularly beneficial that the medical evaluation
unit gives medical practitioners the possibility of changing the
program used by the signal processor to generate the timing
signals. In this way the timing signals supplied by the signal
processor to the stimulation signal generator can be adapted in
accordance with the patient's needs as assessed by the medical
practitioner.
[0030] It is particularly favorable if the medical evaluation unit
is also realized by incorporating elements of a mobile phone so
that communication can take place directly between the medical
evaluation unit and the stimulation signal generator. For example,
should the medical practitioner sense personally, or in response to
an alarm signal generated at the medical evaluation unit, that a
treatment being used on a particular patient is not satisfactory or
is potentially dangerous, e.g. because of some event, such as an
accident, then the ability exists to switch off the stimulation
signal generator directly, thus preventing further treatment until
such time as the problem has been remedied.
[0031] The medical evaluation unit can also be adapted for wireless
transmission of the configuration information to said signal
processor.
[0032] In an alternative embodiment the heart information produced
by the sensing system can be sent not to the medical evaluation
unit but rather by wireless transmission to the signal processor
and the signal processor can be adapted to transmit said heart
information to the medical evaluation unit (by wire or by wireless
transmission). Likewise the medical evaluation unit can then be
adapted to transmit signal configuration information to the signal
processor by wire or by wireless transmission and the signal
processor then takes account of said configuration information when
generating said signal information.
[0033] In a particularly preferred embodiment a plurality of active
electrodes is provided, each having a respective stimulation signal
generator, and the signal processor is adapted to transmit a
respective control signal uniquely associated with one of said
active electrodes to each said stimulation signal generator. For
example, the active electrodes can each have a respective
stimulation signal generator connected thereto via a respective
lead.
[0034] Alternatively, a respective lead can be provided for each
active electrode and means can be associated with a single
stimulation signal generator for applying stimulation signals to
said active electrodes in sequence via said leads.
[0035] When the signal processor has a single transmitter adapted
to transmit control signal information to a plurality of
stimulation signal generators, means are provided for uniquely
associating particular control signals with a respective one of
said stimulation signal generators.
[0036] Alternatively, the signal processor can have a plurality of
transmitters each adapted to transmit control signal information to
a respective one or group of said stimulation signal generators. In
the latter case means are provided for uniquely associating
particular control signals with a respective one of said
stimulation signal generators.
[0037] The signal processor is preferably adapted to transmit
control signal information for a train of stimulation signals
applied to an active electrode, said control signal information
being selected from the group comprising: [0038] amplitude of the
stimulation signals, [0039] frequency of the stimulation signals,
[0040] duration of the train of the stimulation signals, width of
the individual stimulation signals of the train [0041] delay of the
train of the stimulation signals relative to a reference selected
for counterpulsation stimulation and [0042] a recognition code by
which said stimulation signal generator recognizes that said
control signal information is intended for it.
[0043] As indicated above, means is preferably provided at said
stimulation signal generator or at each said stimulation signal
generator for storing control signal information relating to any
respectively associated active electrode.
[0044] It is particularly beneficial when means is provided at said
signal processor for transmitting to said stimulation signal
generator at least one of a program for processing said control
signal information, any subsequent changes to said program and a
new program for processing said control signal information.
[0045] The or each said stimulation signal generator preferably
includes at least some of the following items: [0046] its own
controller, [0047] its own clock, [0048] its own receiver antenna
(RX), [0049] a power circuit and [0050] a battery.
[0051] It is especially beneficial when the or each said
stimulation signal generator includes at least one of the following
additional items: [0052] a transmitter (TX), [0053] means for data
storage, [0054] means for program storage and a [0055] signal
generator trigger.
[0056] An especially beneficial realization of the invention
involves providing the or each said stimulation signal generator
with a program and/or hardware providing a wake mode, a sleep mode
and a death mode. With such an arrangement the battery associated
with the stimulation signal generator only delivers significant
amounts of power during the wake mode, but not during the sleep
mode from which it can be awakened or during the death mode from
which it can no longer be awoken other than by changing or
recharging the battery. Such a stimulation signal generator can be
switched on and off during even one heartbeat in order to save
power and this increases the working life of the battery prior to
changing it or recharging it.
[0057] It is particularly expedient when a display is provided at
least one of said signal processor, said stimulation signal
generator and a medical evaluation unit associated with said
apparatus, said display being for the display of said heart
information signals.
[0058] The display can also be adapted to display data representing
an image of the electrical stimulation applied to said patient. The
display is preferably adapted to display one of an actual ECG-trace
and a representation of an ECG-trace with said image of the applied
electrical stimulation superimposed thereon.
[0059] When a medical evaluation unit is provided it preferably
also has an associated printer for printing said display data.
[0060] The said sensing system is preferably also adapted to send
timing signals to said stimulation signal generator or generators.
This enables the synchronization of the trigger signals (especially
the stored trigger signals referred to above) with the patient's
heart rhythm to be checked.
[0061] The sensing system includes a non-electrical sensor and
transmits data from said non-electrical sensor to said signal
processor. Such a system avoids the electrical stimulation applied
to the patient being incorrectly interpreted as heart
information.
[0062] The sensing system includes an associated signal processor
and a transmitter. This enables the signal processor (which can
again be part of the mobile phone or of a mobile phone related
unit) to compress the heart information and information on
electrical stimulation applied to the patient prior to transmission
to the signal processor or the medical evaluation unit.
[0063] The sensing system can conveniently include at least one of
an A/D converter, a data storage memory and a data compressor. At
least one of said A/D converter, said data storage memory and said
data compressor can be embodied in said associated signal
processor.
[0064] When the sensing system includes a data compressor for
compressing information for transmission to said signal processor
or said medical evaluation unit into packages, the signal processor
and/or the medical evaluation unit is adapted to assemble said data
packages into a continuous data stream, optionally in the form of
an ECG-trace with superimposed electrical stimulation signals.
[0065] A respective code is preferably uniquely associated with
each of said sensing system, said signal processor and said
electrical stimulation signal generator or generators, so that each
item can be uniquely identified.
[0066] The electrical stimulation signal generator preferably has
an associated power supply in the form of a battery and a boost
converter.
[0067] A method of operating an apparatus for the
cardio-synchronized stimulation of skeletal or smooth muscles, but
excluding the heart muscles, in a counterpulsation mode on a
patient having a heart and a cardiovascular system, comprising the
steps of using a sensing system providing heart information from
the patient to communicate said heart information by wireless means
to at least one of a signal processor and a medical evaluation unit
adapted to input configuration data to the signal processor and the
step of using the signal processor to send trigger data to one or
more stimulation signal generators adapted to apply electrical
stimulation signals to electrodes provided on or in the
patient.
[0068] The signal processor can send the trigger data, i.e. the
control signal information, to said one or more stimulation signal
generators by wireless transmission.
[0069] Preferred variants of the apparatus and of the methods are
set out in the claims and in the further description.
[0070] The invention will now be described in more detail by way of
example only and with reference to the accompanying drawings in
which are shown:
BRIEF DESCRIPTION OF THE DRAWINGS
[0071] FIG. 1 is a first schematic diagram illustrating the
operation of the present invention in accordance with a first
embodiment,
[0072] FIG. 2 is a diagram similar to FIG. 1 of a second embodiment
of the present invention,
[0073] FIG. 3 is a further diagram similar to FIG. 1 of a third
embodiment of the present invention,
[0074] FIG. 3A is a diagram related to that of FIG. 3 but showing
bidirectional wireless communication between a configuration input
for a signal processor and the signal processor,
[0075] FIG. 4 is a fourth diagram similar to FIG. 1 showing a
fourth embodiment of the present invention,
[0076] FIG. 5 is a schematic diagram similar to FIG. 4 showing a
possible alternative version of the embodiment of the FIG. 4,
[0077] FIG. 6 is a further diagram similar to FIG. 4 showing a yet
further alternative embodiment of the present invention
[0078] FIG. 7 is a further schematic diagram related to FIG. 4 but
showing a yet further embodiment of the present invention,
[0079] FIG. 7A is a diagram related to that of FIG. 7 but showing
the possibility of bidirectional wireless transmission between a
medical evaluation unit and a signal processor,
[0080] FIG. 7B is a diagram similar to FIG. 7A but showing the
signal processor connected by a lead to or integrated with a
stimulation signal generator,
[0081] FIG. 8 is a schematic diagram showing a first embodiment of
a boost converter capable of use for the present invention to
increase the output voltage of a battery to a higher voltage for
electro stimulation purposes,
[0082] FIG. 9 is a schematic diagram of a second boost converter
similar to that of FIG. 8 but further modified for the purposes of
the present invention,
[0083] FIG. 10 is a schematic diagram of a stimulation signal
generator useful for the present invention and operable with either
the circuit of FIG. 8 or the circuit of FIG. 9,
[0084] FIG. 11A is a schematic diagram representing an ECG trace
taken from a patient with electrical stimulation pulses
superimposed thereon, this being a diagram which can be displayed
at the sensing system, at a medical evaluation unit associated with
the sensing system or at a signal processor associated with the
sensing system,
[0085] FIG. 11B is a diagram showing an enlarged scale the shape of
two sequential biphasic pulses of the electro stimulation pulses
shown in FIG. 11A,
[0086] FIG. 12 is a schematic diagram explaining the operation of
the boost converter of FIG. 8,
[0087] FIG. 13 is a schematic diagram explaining the operation of
the boost converter of FIG. 9,
[0088] FIGS. 14A and 14B are diagrams showing a simulation signal
generator connected to a pair of active and passive stimulation
electrodes suitable for use in any of the embodiments of the
present invention, and indeed in a plan view (FIG. 14A) and in a
side elevation (FIG. 14B),
[0089] FIG. 15 is a diagram showing a patient provided with four
pairs of active and passive electrodes,
[0090] FIGS. 16A and 16B are diagrams similar to FIG. 11A but
showing how the stimulation signals are applied to each pair of
active electrodes in turn, the diagram of FIGS. 16A and 16B
corresponding to FIGS. 6 and 8 of the International application
published as WO 2005/044373, and
[0091] FIGS. 17A and 17B are diagrams corresponding to FIGS. 5A and
5B of WO 2005/044374 showing one possible scheme of electrical
stimulation provided to one pair of active and passive electrodes
for one heartbeat of a patient.
[0092] FIGS. 18A and 18B are diagrams showing further exemplary
embodiments.
DETAILED DESCRIPTION OF THE INVENTION
[0093] In the embodiments of the different figures, the same
reference numerals will be used to identify components which are
identical to each other or have the same function. It will be
understood that the description given for any component having a
particular reference numeral in any one of the figures also applies
to any component having the same reference numeral in any other
figure, unless something is stated to the contrary.
[0094] Turning first of all to FIG. 1 there can be seen an
apparatus 10 for the cardio-synchronized stimulation of skeletal or
smooth muscle present on or in a person 12, or on or in another
patient such as a racehorse or on or in an animal, the said person,
patient or animal having a heart and a cardiovascular system. The
skeletal or smooth muscle can in principle be located anywhere on
the body of the patient.
[0095] The stimulation is effected typically via electrodes such as
14, 16, e.g. in the manner described in the International patent
application with the publication number WO01/013990, or in the
manner described in the International patent applications published
as WO 2005/044373, WO2005/044374 and WO 2005/044372, or in the EP
publication EP1529550, all filed on Nov. 8, 2004, the contents of
which are incorporated herein by reference.
[0096] The apparatus 10 comprises the following items: [0097] at
least one active electrode 14 and at least one passive electrode 16
adapted for attachment to the patient 12 being treated, [0098] a
signal processor 18 having an associated configuration input 20 for
varying at least the time delay associated with the
counterpulsation mode stimulation, [0099] a sensing system 22 for
sensing information relating to the performance of the patient's
heart and for transmission of information signals to the signal
processor 18, the signal processor 18 being adapted to produce
control signal information relating to stimulation signals to be
applied to said the least one active electrode 14 in the
counterpulsation mode, [0100] a stimulation signal generator 24
associated with the at least one active electrode for generating
the stimulation signals which are applied to the at least one
active electrode and [0101] wireless transmission means 26 embodied
in or associated with the signal processor 18 for transmitting the
control signal information from the signal processor 18 to a
receiver 27 at the stimulation signal generator 24.
[0102] In this way the stimulation signal generator 24 applies
stimulation signals to the at least one active electrode in the
counterpulsation mode in accordance with the control signal
information received from the signal processor 18.
[0103] The information relating to the performance of the heart can
be of different types and can, e.g., be selected from the group
comprising: heart rate information (for example from a "Polar"
belt.TM.), ECG information (e.g. from an electrocardiograph or
electrocardioscope), ECG derived information, ECG information and
information resulting from electrical stimulation, ECG derived
trigger signals, R-R information, end of T-wave information, blood
pressure information (e.g. from a blood pressure monitor) and blood
pressure derived information.
[0104] The said sensing system 22 can include at least one of an
invasive sensor, an intercavity sensor, a non-invasive sensor, a
body surface sensor and a remote sensing system detached from the
patient's body.
[0105] The operation of the individual items listed above will now
be explained in more detail. As noted above the stimulation is
applied in the counterpulsation mode as described in the above
referenced WO01/013990. Basically speaking this means that the
initial electrical stimulation is applied to the patient at a time
corresponding to the end of the T-wave of the patients heart rhythm
and more specifically in a time window lying within a range of 5%
of the R-R path before the end of the T-wave and 45% of the R-R
path after the end of the T-wave.
[0106] The precise time at which the initial stimulation is applied
via the electrodes to the patient in synchronization with the
patient's heart rhythm relative to the end of the T-wave is
referred to as the delay. This delay is said to be negative if the
stimulation is applied at a time lying within the range of 5% of
the R-R path before the end of the T-wave and is positive if the
delay is applied within the range of 45% of the R-R path after the
end of the T-wave. It is zero if the initial stimulation
corresponds with the end of the T-wave. Instead of measuring the
delay with respect to the end of the T-wave it is more convenient
to measure it from the preceding R-peak, in which case it is always
positive.
[0107] It will be appreciated by those skilled in the art that the
concept of R-R path lengths, corresponding to the distance between
successive R-peaks of the heart rhythm, e.g., as displayed on an
electrocardiogram, and the point in the electrocardiogram referred
to as the end of the T-wave are well established terms in the
medical field. They are shown, for example, in FIG. 11A and in FIG.
16B. Furthermore, it will be understood that the actual length of
the R-R path, e.g. expressed in milliseconds, is inversely
proportional to the patient's heart rate prevailing at any one time
and is subject to considerable variation depending on the condition
of the heart and on whether the patient is at rest or is
exercising, or is excited, is nervous or performing strenuous
tasks. The end of the T-wave can be predicted from the times at
which the R-peaks occur using the so-called Bazett relationship or
by reference to tables of statistics for various categories of
persons or patients. When using cardiostimulation in accordance
with the present teaching it is necessary to predict, from
historical values of the R-R path length, e.g. from the immediately
preceding R-R path length, or from a recent average value of the
R-R path lengths of several preceding heart beats, when the end of
the next T-wave will occur and to time the triggering of the
electrical stimulation signals to occur at or near to the predicted
end of the T-wave using the appropriate delay.
[0108] Ways of predicting the end of the T-wave from past R-R
values and a discussion of the difficulties which arise can be
found in the aforementioned publication WO 2005/044373. In addition
the application published as WO 2005/044374 describes the way a
muscle contraction can be prolonged with benefit by applying
additional electrical muscle stimulating pulses during each heart
beat after the initial stimulating pulse. The application published
as WO 2005/044372 describes an apparatus and method by which the
electrical stimulating pulses are varied in accordance with a
predetermined pattern or randomly in order to avoid a muscle or
muscle group to which stimulation is applied for a long time from
becoming fatigued. All these techniques require a signal processor
such as 18 to determine the timing of the individual electrical
stimulating pulses relative to the patient's actual sensed heart
rate or rhythm.
[0109] As will be explained later it would be unusual to provide
just a single active electrode. The prior proposals of the present
applicants usually involve four active electrodes associated with a
group of muscles and a stimulation signal is applied to each active
electrode in turn so that each active electrode receives a
stimulation signal every four heart beats. This helps avoid the
muscles becoming fatigued or too accustomed to the applied
stimulation. Although some of the attached figures show only one
active electrode 16, generally a plurality of active electrodes is
present as will be explained later. However, the present teaching
could be used with just one active electrode. The concept of using
multiple active electrodes will be described later with reference
to FIGS. 15, 16 and 17
[0110] It is convenient for the signal processor 18 to deliver
trigger signals which trigger the generation of the actual
electrical stimulation signals applied to the patient in the
stimulation signal generator. One design for a stimulation signal
generator is given in the EP publication EP1529550, the content of
which is also incorporated herein by reference. Another stimulation
signal generator will be described later.
[0111] By providing the signal processor 18 separately from the
stimulation signal generator 24 it is possible to standardize the
stimulation signal generator 24 and to reduce its size so that it
can be carried by the patient without being a burden to the patient
and without inhibiting his activities in any way. Achieving a
further reduction in size of the stimulation signal generator with
a simultaneous improvement in its performance is another aim of the
present teaching. Yet another aim of the present invention is to
enable one stimulation signal generator to be connected to each
pair of active and passive electrodes 14 and 16 so that with a
plurality of active electrodes 14 a like plurality of stimulation
signal generators 24 is present.
[0112] Moreover, by adding intelligence to the signal processor 18
it can be made very flexible and adapted to deal with a variety of
different circumstances. It can also be reprogrammed to take
account of the latest findings, e.g. so as to implement
particularly beneficial pulse timings or pulse profiles or
particularly beneficial courses of treatment, without having to
change the apparatus carried by the patient.
[0113] Equally one signal processor 18 can be used with a variety
of different sensing systems 22 and can be adapted or updated to
derive the information needed from the respective sensing system
22, by processing the signal output from that system to enable the
correct timing of the trigger pulses used to trigger electrical
stimulating pulses at the stimulation signal generator 24 (or
stimulation signal generators if a plurality of them are present).
In addition the signal processor can be designed to deliver trigger
pulses in the millivolt range whereas the stimulation signal
generator delivers electrical stimulating pulses with a
substantially higher amplitude, say up to 50 volts.
[0114] A large number of different variants of the above described
basic apparatus can be realized. For example, as indicated in FIG.
2, when a remote sensing system 22 is provided, the signal
processor 18 can be integrated into said remote sensing system 22
or connected to it by a lead 23. The communication between the
remote sensing system 22 and the signal processor could, however,
also take place via a transmitter 28 and a receiver 30 as indicated
in dotted lines in FIG. 2.
[0115] Because remote sensing systems are not yet well developed it
is however preferred to use a sensing system 22 which is attached
to the patient and it is then preferred for said sensing system 22
to be adapted for wireless transmission of said heart information
to the signal processor 18. This can be achieved by a wireless
transmitter 28 embodied in or associated with the sensing system 22
and an antenna 30 embodied in or associated with the signal
processor 18, as shown in FIG. 1.
[0116] However, as indicated in FIG. 3, even if a sensing system or
unit 22 is used which is attached to the patient, i.e. is not a
remote sensing unit, the signal processor 18 could still be
integrated into the sensing system or connected to it by a lead 23.
Another possibility, which could be used in all embodiments and
which is shown in FIG. 3A, is for the signal processor 18 to be
adapted to receive at the receiver 30 configuration information
transmitted to it from a transmitter 46 at the configuration input.
As a further option, a receiver 38' can be provided at the
configuration input, e.g. to receive information from the signal
processor 18 or from a medical evaluation unit. This has the
advantage that the configuration input 20 can, for example, include
a keyboard and a display screen of useful size which is present at
a location remote from the signal processor which is carried by the
patient, so that the patient is free to move unencumbered by the
keyboard and screen. The wireless connection between the
configuration input 20 and the signal processor 18 and/or between
the configuration input 20 and the medical evaluation unit 32 can
be realized by a mobile phone, a personal digital assistant with
phone function, or any device with transmitter and/or receiver
capabilities, or any standard piece of equipment having a
transceiver, a microprocessor, a memory for storing software and
data, a battery, or other source of power and a clock.
[0117] It can also be beneficial if in accordance with FIG. 4, the
sensing system is adapted to transmit said heart information to a
medical evaluation unit 32 and the medical evaluation unit 32 is
adapted to transmit signal configuration information to said signal
processor 18, with the signal processor 18 taking account of said
configuration information when generating the control signal
information.
[0118] The medical evaluation unit can be a computer, e.g. a
suitably programmed PC, or can take the form of an information
presentation system viewed by a skilled operator who then provides
input information to the signal processor--e.g., via the
configuration input 20, or directly via an input at the medical
evaluation unit which passes via the lead 34 to the signal
processor 18--to ensure the appropriate stimulation signals are
triggered at the stimulation signal generator.
[0119] The configuration input 20 is adapted to input all
parameters to the signal processor 18 which are necessary for it to
generate the required operating or trigger signals for the
stimulation signal generator(s) 24. The medical evaluation unit,
which can be connected to the configuration input 20 (or
communicate with it wirelessly), may well have a need to check the
operating data currently input at the configuration input 20, and
thus the configuration unit 20 is designed to make the required
information available to or accessible by the medical evaluation
unit 32. Equally, it may be useful for the signal processor 18 to
not only receive operating parameters from the configuration input
20 (or from the medical evaluation unit 32) but for the actual
operating parameters being used by the signal processor to be
available to or accessible by the configuration input 20 and/or the
medical evaluation unit 32, so that transmission of said operating
data from the signal processor 18 to the configuration unit 20
and/or to the medical evaluation unit 32 is also preferably
provided for.
[0120] More specifically, the medical evaluation unit 32 is adapted
to display and/or print out the signals from the sensing system,
e.g. in the form of an electrocardiogram, or simply in the form of
a succession of R-R peaks possibly together with entries showing
the positions of the T-waves or the predicted ends of the T-waves,
together with signals representative of the applied stimulation.
This enables a skilled operator viewing the display to control the
signal processor, either by signals input by him at the medical
evaluation unit or at the signal processor (optionally at the
configuration input or another dedicated input) to change the
stimulation treatment applied to the patient. If the medical
evaluation unit 32 is realized as a computer or includes a
microprocessor--which will normally be the case--then it is
preferably programmed to control the signal processor to generate
trigger signals for triggering the stimulation signal generator(s)
to apply the appropriate stimulation signals to the patient. The
position at which the control signals from the medical evaluation
unit enter the signal processor can also be considered to be a
configuration input.
[0121] In the example of FIG. 4 a non-remote sensing system 22 is
used, i.e. one attached to the patient and signals from the sensing
system 22 are transmitted by a lead 25 to the medical evaluation
unit 32. As mentioned the medical evaluation unit 32 is connected
via a lead 34 to the signal processor 18. As before, the signal
processor 18 transmits the timing signals for the electrical
stimulation pulses via the transmitter 26 to the receiver 27 at the
stimulation signal generator.
[0122] It is, however, preferable for the medical evaluation unit
32 to be adapted for wireless transmission of said configuration
information to said signal processor 18 as shown in FIG. 5. This
can be done by means of a transmitter 36 at the medical evaluation
unit which communicates with a receiver 30 at the signal processor
or a receiver 38' at the configuration input 20. In an alternative
(not shown) the receiver 30 can be integrated with the transmitter
26 and configured as a transceiver. This arrangement enables the
medical evaluation unit and the signal processor to be housed in
different rooms and indeed at completely separate remote locations.
For example, the medical evaluation unit could be located in a
special facility in a hospital and the signal processor in a
doctor's practice in a different building, town or country. It is
particularly preferable if as shown in FIG. 6, the sensing system
is adapted to transmit said heart information to said medical
evaluation unit by wireless transmission. For this purpose the
sensing system 22 has a transmitter 28 and the medical evaluation
unit a receiver 38.
[0123] This variant has the advantage that the patient can be
completely mobile and located a considerable distance from both the
medical evaluation unit 32 and the signal processor 18. The patient
only needs to carry on his person the sensing system 22 with
transmitter 28 and the stimulation signal generator(s) 24 with
receiver 27. Both the sensing system (22) and the stimulation
signal generator(s) 24 can be made very small, so that the
patient's mobility is not hindered and he can be subjected to
long-term treatment while going about his daily life. In the
variant shown in FIG. 6 the receiver 38 and the transmitter 36 at
the medical evaluation unit can be combined into a transceiver.
Even if the patient carries the signal processor 18 in the form of
a mobile phone on his person, which is one possibility, this does
not hinder him unduly because he is not wired to the phone.
[0124] It would also be possible to combine the signal transmitter
28 at the sensing system 22 and the signal receiver 27 at the
stimulation signal generator 24 into a single transceiver.
Moreover, the stimulation signal generator and the sensing system
could be integrated into a single device as indicated by the dotted
outline 40 in FIG. 6.
[0125] One particularly favorable realization of such a single
device would be a dedicated unit which would, for example, take the
form of a mobile phone, a personal digital assistant with phone
function or any standard piece of equipment having a transceiver, a
microprocessor, a memory for storing software and data, a battery
or other source of power, a clock and the necessary interface(s)
for connection to the sensor or sensors 21 at the patient, such as
ECG sensors, and to active and passive electrodes 14, 16. The
dedicated unit could also include a screen for displaying a trace
symbolizing and relating to the positions of the R-R peaks and the
end of the T-wave and possibly a signal relating to the stimulation
applied. The realization as a mobile phone is particularly
attractive since a mobile phone has all the necessary elements of
the dedicated unit, or could be provided with additional interfaces
if necessary. In particular a mobile phone has plenty of storage
capacity for storing software and data relating to the additional
functions it has to perform for implementing the present teaching.
Indeed it could be further developed to function as a heart monitor
and provide timely warnings to a receiver at, e.g., the medical
evaluation unit, if a heart attack is incipient--enabling remedial
action to be taken at an early stage, e.g. in a telephone call from
an operator at the medical evaluation unit to the patient
concerned, or by alerting an emergency service.
[0126] Moreover, the signal processor 18 can also take the form of
a dedicated unit which could, for example, take the form of a
mobile phone, a personal digital assistant with phone function or
any standard piece of equipment having a transceiver, a
microprocessor, a memory for storing software and data, a battery
or other source of power, a clock and an input for configuration
data and/or control signal information. It could also comprise a
mobile phone related unit having one or more signal receivers,
transmitters in addition to a telephone aerial or aerials.
[0127] In another variant shown in FIG. 7 the sensing system 22
transmits heart signal information to the signal processor 18 and
the signal processor is adapted to transmit or relay heart
information to the medical evaluation unit 32 via a lead 44 and
said medical evaluation unit is adapted to transmit signal
configuration information to said signal processor via the lead 34.
The signal processor 18 then takes account of the configuration
information when generating said signal information.
[0128] In an alternative shown in more detail in FIG. 7A the signal
processor 18 is adapted to transmit said heart information to said
medical evaluation unit 32 by wireless transmission as indicated by
the receiver 38 shown in dotted lines at the medical evaluation
unit and the medical evaluation unit 32 is adapted for wireless
transmission of said configuration information via the transmitter
36 to the receiver 30 at the signal processor 18. In this case the
receiver 30 and the transmitter 26 can form one transceiver and the
receiver 38 and the transmitter 36 can form a second transceiver.
Again the transmitter 28 and the receiver 27 can also be combined
into a transceiver and all transceivers can be realized as a mobile
phone or as a mobile phone related unit.
[0129] FIG. 7B shows possible further modifications of the
embodiment of FIG. 7A. In one modification the configuration input
20 communicates with the signal processor 18 by wireless
transmission, as discussed in connection with FIG. 3A and/or with
the medical evaluation unit 32 by wireless transmission. For
example, the transmitter 46 at the configuration input 20 can
communicate with the receiver 30 at the signal processor 18 and/or
with the receiver 38 at the medical evaluation unit 32. Moreover,
the transmitter 26 at the signal processor can transmit information
to the receiver 38' at the configuration input 20. The receiver 38'
at the configuration input can alternatively or additionally
receive information from the medical evaluation unit by wireless
transmission from the transmitter 36 provided at the medical
evaluation unit 32. For example, the medical evaluation unit could
reset the parameters of the stimulation being applied to the
patient by sending new configuration data either directly to the
signal processor 18 or via the configuration input 20 and could
also send a message to the configuration input 20 advising the
patient of the changed parameters when he views or switches on the
screen associated with the configuration input 20.
[0130] Furthermore, FIG. 7B shows by way of the line 48 that the
signal processor could also be connected by a lead to the
stimulation signal generator(s) 24. If a plurality of stimulation
signal generators 24 are present, then the signal processor 18
could be connected to one or more of them by a lead and the other
signal generators could either be interconnected by leads or
communicate with each other wirelessly.
[0131] In a further alternative the signal processor could be
integrated with all or one of the stimulation signal generators 24
and could communicate wirelessly with each stimulation signal
generator 24. In these cases, i.e. when the signal processor is
connected by a lead to one or more stimulation generators 24 or is
integrated with one or more of them, the signal processor 18 is
physically carried by the patient. This is not a problem because
the signal processor 18 can be made very small and requires little
power to drive it. This power can readily be supplied by the
battery associated with each stimulation signal generator. It is
later described with reference to FIGS. 14A and 14B how a
stimulation signal generator can be used for each pair of active
and passive electrode 14, 16 and can, for example, be clipped to
them. It is entirely possible and indeed sensible to integrate the
signal processor 18 into one of the stimulation signal generators
24 or possibly to have a signal processor 18 integrated into each
of the stimulation signal generators 24. This would make it
possible to use one standard integrated component (stimulation
signal generator+signal processor) for each pair of electrodes with
economy of scale due to the need to manufacture only one
standardized device. Moreover, since each stimulation signal
generator has its own battery, the individual batteries can be kept
relatively small and the distributed weight is not a problem for
the patient.
[0132] In addition, it should be noted that the embodiment of FIG.
3A can also be modified to include a medical evaluation unit 32
communicating with one or both of the configuration input 20 and
the signal processor 18 by wireless transmission (optionally
bidirectional as discussed in connection with FIG. 7B).
[0133] As mentioned above one of the objects of the present
invention is to improve the design of the stimulation signal
generator to make it lighter, compacter and to improve the working
life of the batteries that are used. One way of achieving this is
to avoid a bulky and heavy transformer for the power circuit.
[0134] The reasoning behind the concept is as follows: At low
battery voltage Vo and at a given maximum stimulation end voltage
Vmax of a power circuit, the transformer can become too bulky and
too heavy, because the ratio of the transformer would have to be
increased to reach Vmax, the more Vo is being reduced. As an
example: at Vo=7.4 V and at Vmax=45 V, a standard transformer ratio
of, e.g., 1:10 can be used by increasing the output voltage from 5
V to 50 V, allowing Vmax of 45 V without distortion. At Vo of 1.2 V
a ratio of 1:50 would have to be used to increase the output
voltage from 1.0 V to 50 V, allowing Vmax of 45 V without
distortion. Such a transformer would be inordinately heavy. The
basic solution provided by the present invention is to use a boost
converter which is shown in FIG. 8 It consists of an inductor 50
"L", a diode 52 "D", a capacitor 54 "C", a switching component 56
"So" and a boost controller 58. In an improved version of the boost
converter a second switching component 60 "Soo" shown in FIG. 9 is
used which is connected to the battery voltage supply Vo, and to
ground, GND. The complete circuit shown in FIG. 10 further involves
a switching set up, e.g., the form of a so-called H-Bridge
involving the switches S1, S2, S3, S4, is connected to the two
outlets (+Vx and GND) to allow the desired switching to be
controlled by an H-Bridge controller. In integrated circuits, the
voltage Vo from the battery is nowadays typically equal to 1.2
V.
[0135] Any switching component can be used for the switches So,
Soo, S1, S2, S3 and S4, such as electronic analog switches,
transistors, triacs, etc., whatever is best suited for micro
integration to keep dimensions small. There are many ways how such
a booster converter can be switched. The following describes one
specific example. The description below shows, as a preferred
example, how a desired constant voltage signal, a fully balanced
plus/minus signal as shown in the impulse diagram of FIG. 11, can
be achieved to be applied to a patient using a booster
converter.
[0136] The diagram of FIG. 11 shows in FIG. 11A a typical e.c.g.
trace with the repeating signal elements QRSTPQR . . . as well
known to any cardiologist. Superimposed on this trace and starting
at the end of the T-wave; i.e. after the time QT in FIG. 11A is a
stimulation signal comprising a first train of pulses having a
duration D with two sequential pulses of this train (which are
representative of all the pulses) being shown to an enlarged scale
in FIG. 11B. It is noted that the relative amplitudes of the pulses
in FIG. 11A are to different scales. In practice the amplitude of
the stimulation pulses during the interval D is in the range up to
.+-.45 volts whereas the peak amplitudes of the R-peaks are of the
order of millivolts.
[0137] The graph of FIG. 11B shows how the impulse signal Vp varies
as a function of time (with time being shown to an expanded scale
relative to FIG. 11A). The pulses of FIG. 11B are so-called
biphasic pulses. That is to say the impulse signal Vp increases
from zero to a maximum with a relatively sharp rise time, dwells at
the peak amplitude for a time essentially equal to W/2, then drops
sharply to a minimum value at which it persists for a further time
equal to W/2 following which it returns to zero and remains at this
level for a period Tb prior to repeating again. Thus, the desired
biphasic signal is essentially a rectangular wave signal with
positive and negative components of balanced amplitude, with the
pulses having a duration W shorter than the pulse interval Tb. This
signal results in a minimum net electrical loading of the patient
and a minimum net consumption of energy to achieve a particular
muscle contraction and maintain it for a period of time which is
actually greater than D and up to two to three times the duration
D. Particularly preferred excitation signals are described in
WO2005/044374.
[0138] To achieve the positive constant voltage flank of FIG. 11B
using the circuit of FIG. 8 the switching component So is switched
continuously by the boost controller to build up in small digital
steps to the desired maximum voltage V as shown in FIG. 12 as one
of the parameters set by the controller to the signal generator and
thus to the boost controller in order to regulate the desired
constant output voltage+Vx, for the duration D of the package of
impulse trains, see the impulse diagram of FIG. 11A. For this
purpose the boost controller has a feedback of the effective
voltage Vc of the capacitor C from the positive output compared to
ground "GND" so it can regulate the value Vx to become and stay
constant at the set value Vs. The boost controller uses a clock
(not shown) to open and close the switching component So at high
frequency.
[0139] Initially, the H-Bridge controller closes switches S2+S4
(S1+S3 are open). The active and passive electrodes (14, 16) are
connected to GND and Vp on the patient=0 V. At the desired time Td
(2), the controller closes switch S3+S2 (S1+S4 are open). As a
consequence +Vx is connected to the active electrode 14 on the
patient and the GND is connected to the passive electrode 16 on the
patient. A current corresponding to the actually prevailing voltage
difference Vp and the resistance and capacitor value of the human
body flows between the electrodes.
[0140] Because the switch So is continuously closed and opened and
closed and opened at the frequency determined by the boost
controller, and because the diode D prevents current flowing back,
the capacitor is charged and increased in its voltage each time the
switch So is opened and, as a consequence, the voltage on the
patient Vp is incrementally increased (3) until after time Tx the
set voltage Vs is equal to the voltage Vx, so the voltage on the
patient now has become Vp=+Vx (4). The voltage gradient increase is
proportional in time to the frequency of the switching of So and
the voltage steps are proportional to the selected steps.
Typically, a 1 MHz boost controller 58 could e.g., boost the
voltage from 0 V to 50 V in 20 steps per volt, each requiring one
switching step in the time Tx of 1 milliseconds (50 V times 20
steps/V=1000 steps; 1000 steps divided by 1,000,000 steps/sec=0.001
sec or 1 millisecond.
[0141] The switching component So continues to be switched with
S3+S2 being closed (S1+S4 are open) to recharge the capacitor in
order to compensate the current flowing to the patient. The voltage
+Vx=Vp is applied to the active electrode 14 of the patient and the
corresponding current flows for the desired time Tw.
[0142] To achieve the negative constant voltage flank at the
desired time Tw1 (5), the H-Bridge controller switches instantly
and closes S1+S4 (S3+S2 are now open): Now the active electrode 14
on the patient is connected to GND and the passive electrode 16
becomes -Vx, because the voltage Vc on the capacitor cannot jump.
The voltage on the patient Vp is now the negative voltage -Vx and a
corresponding current now flows from the passive electrode to the
active electrode. This inversion of the voltage +Vx at the output
of the boost converter is indicated in FIG. 12 by the dotted line.
The diagram shows that the output of the boost converter always
stays at the constant level +Vx, however it is the switching of the
H-Bridge, which reverses the effect Vp on the patient. The boost
controller continues switching the switch So and the negative
voltage -Vx is being kept on the patient for a second period Tw2
(6). This is how an identical, but inverted (negative) signal can
be produced simply by switching the H-Bridge correspondingly.
[0143] After period Tw2 has elapsed, the H-Bridge is now switches
at point (6) and closes S2+S4 (S1+S3 are open). Now passive and the
active electrodes 16, 14 are now again connected to GND and the
human capacitor is discharged instantly and with this the voltage
Vp on the patient drops immediately to zero. Switching of So can
now either rest to save battery power or it continues to be
switched and with this the capacitor keeps its charge for a break
corresponding to the period Tb (7).
[0144] After the period of the break Tb (7) (the break is being
calculated as the interval time I, minus impulse width W (see FIG.
11B) has elapsed, the H-Bridge controller switches closes switch
S3+S2 (S1+S4 are open). Now the charged capacitor can discharge
instantly the positive voltage +Vx=Vp to the patient and the
process described above resulting in positive and negative flanks
is repeated.
[0145] After the period of the duration D has ended with a last
switching of the H-bridge closing S2+S4 (8), hereby connecting both
the active and passive electrode to GND and Vp=0, So switching can
be stopped and the capacitor can either be discharged by closing
S1+S2, for instant discharging of the capacitor, or alternatively,
the capacitor maintains its charge until the next set value Vs
defines whether the voltage has to be increased or decreased.
[0146] So for the next impulse of trains the process can be started
again to design a constant voltage signal having the same or a
different amplitude A. When the capacitor has not been discharged
it can be boosted to the newly desired level (up or down).
[0147] Using such a boost converter and an H-Bridge any signal can
be designed as a function of time at the outputs. The example
described and shown is simply given as one possible example.
[0148] The preferred embodiment of the boost converter and its
operation will now be described with reference to FIGS. 9 and
13.
[0149] As noted above, the FIG. 9 embodiment includes an additional
switching component Soo in comparison to FIG. 8 and this switching
component Soo is provided and is also switched by the boost
controller when required.
[0150] The setup works in principle in exactly the same manner as
described with reference to the embodiment of FIG. 8, except that,
for achieving the positive flank for the first time, the switch Soo
of the positive booster converter is opened meaning that the
designed positive flank of the voltage increase to Vx cannot be
delivered to the active electrode 14 and the built up voltage Vx is
stored in the capacitor. At the desired time Td2 (9), Soo is closed
and the stored voltage Vx is instantly delivered to the active
electrode, without the design-related delay Tx. The buildup of the
desired voltage +Vx in the capacitor has to be done prior to the
time Td-Tx to allow an instant delivery of the full voltage Vx.
[0151] All other steps remain the same as described with reference
to FIGS. 8 and 12.
[0152] It remains to be said, that some effort is required to
integrate switching component Soo into a micro integrated circuit,
but there are ways how it can be done. Although the diagram of FIG.
13 is ideal, it is acceptable to use only the setup of FIG. 12 as
an acceptable compromise.
[0153] As indicated above a plurality of pairs of active/passive
electrodes 14, 16 are preferably provided and each pair of
active/passive electrodes 14, 16 has its own stimulation signal
generator 24 or power circuit 24 so that reference will be made
here to multiple power circuits. Each power circuit of the multiple
power circuits is placed directly onto a respective pair of active
and passive electrodes, placed in the vicinity of each other onto
the patient's skin avoiding the need for wiring between a power
circuit unit and the electrodes. One terminal of each electrode is
used to connect and carry the respective power circuit unit thus
keeping the wiring to a minimum. Each stimulation signal generator
24 is equipped with switching components to form a so-called
H-Bridge, S1-S4 and one boost converter is powered from a battery
of a design voltage V0 as described above with reference to FIG. 8
or FIG. 9.
[0154] The stimulation signal generator receives three different
pieces of information. First of all it receives [0155] A) delay
information, i.e. the exact moment when the power circuit has to
stimulate relative to the heartbeat, from the signal processor 18
via the transmitter 26 of the signal processor and the receiver
(RX) 27 of the stimulation signal generator [0156] B) parameters,
i.e. combinations of amplitude, frequency, duration, signal width
of single or multiple trains of stimulation packages from the data
storage 60, where these parameters are stored. Such parameters are
received via the receiver RX, whenever a corresponding new
parameter is being sent by wireless communication from the signal
processor 18. The delay information can also be stored in the
memory or data storage 60 if it remains substantially constant and
can be updated as required (depending e.g. on the patient's heart
rate) from the signal processor 18. [0157] C) the boost controller
58, having a clock (not shown), which controls the signal generator
and the H-Bridge controller 64 in such a way, that they can deliver
the wanted signal with the stored parameters at the correct delay
time.
[0158] Thus, the receiver RX 27 receives from the transmitter 26 of
the signal processor 18 addressed (coded) wireless information:
[0159] a correct delay for each heartbeat, [0160] parameters
whenever they have been changed, and [0161] sleep and wake up
information in order to put the signal generator to sleep when not
required in order to save battery power
[0162] The stimulation signal generator 24 preferably includes a
transmitter TX (which may be the transmitter 28 or could be a
separate transmitter) can provide feedback information to the
signal processor (e.g. via the receiver 30) such as: [0163]
information on whether the stimulation signal generator is asleep
or awake (ready to receive parameters) [0164] confirmation that a
parameter change has been received and stored [0165] information on
the remaining battery capacity etc.
[0166] Each power circuit unit (stimulation signal generator 24)
has its own wireless communication means (antenna), common or
separate for RX and TX (e.g. 27, 28), depending on the means of
wireless communication.
[0167] Turning now to FIGS. 14A and 14B there can be seen a pair of
active and passive electrodes 14, 16 which are provided with
terminals 70, 72 onto which a respective stimulation signal
generator 24 is clipped so that it has electrical contact to the
two terminals 70, 72. The stimulation signal generator 24 can, for
example, be designed as shown in FIG. 10 and can have its own
antenna 74 which can be simply a receiver antenna 27 as shown in
FIG. 10, or an antenna for a combined receiver/transmitter 27, 28
which is also indicated in FIG. 10.
[0168] Turning now to FIG. 15 there can be seen four pairs of
active and passive electrodes 14', 16'; 14'', 16''; 14''', 16''';
14'''', 16'''''', each provided with a respective stimulation
signal generator 24', 24''; 24''', 24''''. Instead of providing
each stimulation signal generator 24 with its own antenna 74, which
can be a receiver antenna or a transceiver antenna, each of the
stimulation signal generators could be connected to a transceiver
76 illustrated here in the form of a mobile phone, and indeed via
leads 78', 78'', 78''', 78''''. Equally, if a mobile phone is used
in this way it can be connected to the ECG electrodes 21', 21'',
21''' or to any other suitable sensing system. Again, the
connection in this case is by way of leads 80', 80'', 80'''.
Because the leads 78', 78'', 78''', 78'''' and 80', 80'' and 80'''
are optional they are shown in broken lines. Since very light leads
can be used they do not pose a significant inconvenience for the
patient
[0169] FIGS. 16A and 16B now illustrate how the pairs of active and
passive electrodes are energized. It is noted that FIG. 16B refers
to channels 1, 2, 3 and 4 which are the channels which are
associated with the four electrode pairs 14', 16'; 14'', 16'';
14''', 16'''; 14'''', 16'''''' and the associated stimulation
signal generators 24', 24''; 24''' in FIG. 15.
[0170] The channels 5, 6, 7 and 8, which are an optional extra,
could be associated with four further pairs of active/passive
electrodes with associated stimulation signal generators (not
shown). As described in WO 2005/044373, such systems can be used to
improve blood transport to different areas of the body or to
improve lymph transport from various areas of the body. In order to
achieve such transport it is necessary for the electrical
stimulation signals in the group of channels 5 to 8 to be offset
from those in the channels 1 to 4. This will not be explained
further here because the concept is described and claimed in detail
in the above referenced PCT application.
[0171] The schematic representation of an ECG trace at the top of
FIG. 16B shows four R-R peaks corresponding to four heartbeats and
it can be seen that a first electrical stimulation signal D'
(corresponding to D in FIG. 11A) is applied to the first electrode
pair 14', 16' via channel 1 during a first heartbeat. A second
train of electrical stimulation pulses D'' is then applied during a
second subsequent heartbeat via the channel 2 to the pair of
electrodes 14'', 16''. During the third heartbeat a further train
of electrical stimulation pulses D''' is applied via channel 3 to
the third pair of electrodes 14''', 16''' and during a fourth
heartbeat a further train of electrical stimulation pulses D'''' is
applied via the channel 4 to the fourth pair of electrodes 14'''',
16''''. During a fifth heartbeat (not shown) a further train of
electrical stimulation pulses corresponding to D' is again applied
via channel 1 to the first pair of electrodes 14', 16' and so
on.
[0172] FIG. 16A again illustrates the offset between the two
channel groups channels 1 to 4 and channels 5 to 8, and it can be
seen that the stimulation signal applied to muscle group 1, for
example the muscle group with which the electrode pair 14', 16'
cooperates, has a duration which is considerably shorter than the
muscle contraction which it generates.
[0173] In FIG. 11A and in FIGS. 16A and 16B there is shown a
relatively straightforward method of muscle stimulation involving
five individual biphasic pulses D. These five individual biphasic
pulses are illustrated again in FIG. 17A, together with possible
values for the amplitude of the biphasic pulses in volts and
durations shown in milliseconds.
[0174] It is, however, possible to use additional stimulating
pulses after the initial group of stimulating pulses D in order to
prolong the muscle contraction but minimizing the electrical input
into the patient which is beneficial both for the patient and for
the lifetime of the batteries involved in the stimulation signal
generators.
[0175] In the scheme shown in FIG. 17B the first group of pulses D
is followed by individual pulses E, F which, in this example, are
single biphasic pulses identical to the individual biphasic pulses
of the group D, but with a greater pulse interval between the
pulses. In practice there can be many more individual pulses such
as E and F. Also there are a large number of different variants of
such stimulation schemes and these are explained in detail in WO
2005/044374. They will not be discussed here in detail.
[0176] FIG. 18A shows a further apparatus. In the present example
the signal processor 18 has a configuration input 20. The signal
processor 18 is configured to produce control signal information
relating to stimulation signals to be applied to said at least one
active electrode 16 in the counterpulsation mode. The signal
processor is configured as a device with wireless transmitter and
receiver capabilities to wirelessly transmit and/or receive at
least one of control signal information, sensing information and
signal configuration information.
[0177] FIG. 18B shows a further apparatus. In this case the signal
processor 18 is included in a device such as a mobile phone, a
personal digital assistant with phone function, or any standard
piece of equipment having a transceiver, a microprocessor, a memory
for storing software and data, a battery, or other source of power
and a clock. The software stored in the device is relevant to the
operation of the signal processor 18 and the device further
includes data relating to the patient's heart rhythm and the
performance of the heart and data relating to the stimulation
applied or to be applied is stored in the device. The device is
capable of wireless transmission and reception and receives
wireless data from the sensing system 22 and transmits wireless
data to the active electrode 16 for the purpose of therapy.
* * * * *